How could i make my frame difference method as real time ?

[tina]

Hi ,

I  am calculating time of my  processing .

my code : http://codepad.org/BSirion5 

I grabbed only two frames that  

diff = f1 -f2 at first loop iteration ,.

When i run code.  i checked program processing time  which some thing like this

Initailze camera mood....  
detection time = 226.576 ms
detection time = 233.211 ms
detection time = 281.371 ms
detection time = 273.171 ms
detection time = 227.692 ms
detection time = 229.399 ms
detection time = 262.038 ms
detection time = 242.937 ms
detection time = 208.642 ms
detection time = 270.872 ms
detection time = 287.31 ms
detection time = 212.902 ms
detection time = 265.157 ms
detection time = 265.785 ms
detection time = 252.408 ms
detection time = 238.049 ms
detection time = 265.009 ms
detection time = 281.793 ms
detection time = 257.836 ms
detection time = 218.414 ms
detection time = 261.425 ms
detection time = 268.683 ms
detection time = 238.207 ms
detection time = 222.844 ms
detection time = 261.017 ms
detection time = 220.808 ms
detection time = 225.111 ms
detection time = 263.729 ms
detection time = 252.442 ms
detection time = 211.466 ms
detection time = 276.157 ms
detection time = 290.334 ms
detection time = 226.761 ms
detection time = 289.755 ms
detection time = 264.321 ms
detection time = 270.401 ms
detection time = 211.406 ms
detection time = 264.604 ms
detection time = 253.199 ms
detection time = 220.085 ms
detection time = 221.343 ms
detection time = 254.793 ms
detection time = 232.024 ms
detection time = 217.092 ms
detection time = 260.867 ms
detection time = 230.145 ms
detection time = 225.672 ms
detection time = 265.954 ms
detection time = 283.63 ms
detection time = 245.943 ms
detection time = 232.605 ms
detection time = 268.429 ms
detection time = 211.795 ms
detection time = 234.027 ms
detection time = 262.869 ms
detection time = 233.799 ms
detection time = 239 ms
detection time = 261.682 ms
detection time = 260.83 ms
detection time = 219.194 ms
detection time = 266.752 ms
detection time = 249.426 ms
detection time = 265.998 ms
detection time = 233.632 ms
detection time = 251.878 ms
detection time = 257.261 ms
detection time = 219.452 ms
detection time = 256.234 ms
detection time = 264.546 ms
detection time = 289.183 ms
detection time = 215.055 ms
detection time = 267.02 ms
detection time = 253.985 ms
detection time = 226.334 ms
detection time = 220.25 ms
detection time = 255.339 ms
detection time = 214.689 ms
detection time = 242.647 ms
detection time = 258.114 ms
detection time = 239.591 ms
detection time = 248.238 ms
detection time = 245.402 ms
detection time = 266.547 ms
detection time = 220.903 ms
detection time = 248.863 ms
detection time = 254.537 ms
detection time = 211.379 ms
detection time = 233.58 ms
detection time = 268.39 ms
detection time = 218.566 ms
detection time = 220.327 ms
detection time = 261.507 ms
detection time = 238.651 ms
detection time = 237.025 ms
detection time = 258.865 ms
detection time = 267.539 ms
detection time = 209.787 ms
detection time = 260.823 ms
detection time = 267.556 ms
detection time = 216.067 ms
detection time = 238.266 ms
detection time = 267.508 ms
detection time = 276.625 ms
detection time = 227.174 ms
detection time = 262.231 ms
detection time = 271.494 ms
detection time = 257.582 ms
detection time = 211.41 ms
detection time = 264.637 ms
detection time = 228.064 ms
detection time = 223.122 ms
detection time = 262.731 ms

that mean time is taking too much only  for  frame rate 4 ..
How could is that possible while my camera diver have set frame rate 30fps .

Is it due to my grabbed frames that is only 2 . and may be thats depend on loop iterations.

AS i understand . i think the time like 211.379 ms  worked for two frames at only two iteration,. thats my time tells frame rate 4fps ..  

Is that mean i should grab  15 frames like

diff = f 1 - f2
diff = diff - f3
diff = diff - f4 '
diff = diff - f5

 soooooooo on
diff = diff - f15

Processing generally  looks real time processing  > 15 or 12 frame per sec ..

What do i do ? Is that the reason that frame difference method is not good .

Is frame difference only applied between two frames . ?

My program is not real time because it leaves previous frame shadow  during my hand motion  ,.  

Can you please guide me  in frame difference to make it real time . thanks